Geology (from the Ancient Greek γῆ, gē, i.e. "earth" and -λoγία, -logia, i.e. "study of, discourse") is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also refer to the study of the solid features of any terrestrial planet or natural satellite, (such as Mars or the Moon).
The increasing number of factors playing a role in the various complexes of natural phenomena are the origin of new, so-called emergent, laws and characteristics. Based on this principle of emergence, a hierarchy of sciences can be distinguished: physics-chemistry-geology-biology-psychology.